The prior art U.S. Pat. No. 5,126,407 describes mixtures comprising:
from 85 to 65 parts of polyamide 6.6; PA1 from 15 to 30 parts of a copolymer of ethylene and acrylic acid in the proportions 90/10, which is neutralized 70% with zinc; PA1 from 0.1 to 3 parts of a styrene-maleic anhydride copolymer. PA1 from 90 to 65 parts of polyamide 6.6 PA1 from 10 to 30 parts either of an ethylene-acrylic acid copolymer which is neutralized to 70% with zinc or of a mixture of polyethylene and grafted polyethylene PA1 from 0.1 to 3 parts of a styrene-maleic anhydride copolymer PA1 from 0.1 to 30 parts of fibres of a fluoropolymer.
The comparative examples show that the presence of the styrene-maleic anhydride copolymer is necessary in order to give a sufficient melt strength and to allow blow moulding of the alloys of the PA 6.6 and of the neutralized ethylene-acrylic acid copolymer and their conversion into hollow bodies.
U.S. Pat. No. 5,122,570 is similar to the abovementioned prior art except that the neutralized ethylene-acrylic acid copolymer is replaced by a mixture of polyethylene and grafted polyethylene.
U.S. Pat. No. 4,966,941 describes mixtures comprising:
The comparative examples show that the presence of the styrene-maleic anhydride copolymer and of the fluoropolymer fibres is required to enable the alloys of the polyamide with either the neutralized ethylene-acrylic acid copolymer or the polyethylene and the grafted polyethylene to be blow moulded and converted into hollow bodies.
EP 624 623 describes films made up of a mixture of 45 parts of a styrene-maleic anhydride copolymer of mass Mw 110,000, which is optionally imidized, and 55 parts of a copolymer having polyamide blocks and polyether blocks. These films withstand repeated folding.
The prior art has not described the technical problem of the present invention.